This invention relates, in general, to molded plastic containers and, in particular, to improved tamperproof closure systems for such containers. More particularly still, it relates to an improved sealed plastic container having a cap associated therewith which prevents inadvertent opening of the container and indicates when the container has been opened.
Various food, medical, and household products presently are being packaged in molded plastic containers. Presently, most of these containers are adapted to be easily opened. In particular, sealed molded plastic containers are used to dispense sterile medical liquids in various medical procedures. For example, one type of container, called an intravenous solution container, is used for the administration of parenteral solution into a patient's vein. Other types of medical liquid containers are used to dispense irrigating liquid to a surgical site.
All of these sterile medical liquid containers have a common purpose of maintaining the sterility of their liquid contents during storage, shipping and dispensing. An extremely critical portion of these containers is their closure system. The closure system must maintain a bacteria-tight seal until intentionally opened. Conversely, all of these closures must be easy for the nurse or physician to open.
One means of providing a bacteria-tight seal on a container closure is to make the closure an integral part of the container. This can be done by forming the container and closure as a one-piece unit, such as blow molding, or the closure can be fused or bonded to the container. To open the container, a frangible or separable portion of the closure or bottle is broken or torn. Examples of such closure systems may be found in U.S. Pat. Nos. 2,214,255; 2,414,420; 3,314,564; 3,484,012; 3,493,140; 3,974,008; and 4,153,174. Nevertheless, a continuing problem remains in such closure systems in preventing inadvertent opening, and in indicating when the container has been opened.